Add new views and styles for music application

- Created new CSS files for styling the application, including home.css and style.css.
- Implemented 403 and 404 error views with appropriate messages and navigation.
- Developed a dump view to display deleted elements with restoration options.
- Enhanced home view to include music search functionality and display results.
- Added listplay view for managing music playlists, including creation and deletion options.
- Implemented loadmusic view for uploading new music with necessary fields.
- Created login and register views for user authentication.
- Developed sound view to display individual music tracks with playback controls and options for liking and deleting.
- Updated menu view to include navigation links based on user authentication status.

request/post/login.post.php

@@ -0,0 +1,11 @@
+<?php
+
+$redirect = "./?view=$view";
+if (isset($_POST['username']) && isset($_POST['password'])) {
+    if ($user->isAccess($_POST)) {
+        $redirect = './';
+    }
+}
+header("location: $redirect");
+
+?>